Obesity is a condition in which the natural energy reserve, stored in the fatty tissue of humans and other mammals, is increased to a point where it is associated with certain adverse health conditions. Although obesity is an individual clinical condition, it is increasingly viewed as a serious and growing public health problem. Excessive body weight has been shown to be a predisposition to various diseases, particularly cardiovascular diseases, diabetes mellitus type 2, sleep apnea and osteoarthritis.
The main treatment for obesity is to reduce body fat by ingesting fewer calories and increasing exercise. A beneficial side effect of exercise is to increase muscle, tendon, and ligament strength, which helps to prevent injury from accidents and vigorous activity. Diet and exercise programs produce an average weight loss of approximately 8% of total body mass (excluding results from those individuals who drop out of such programs). Not all dieters are satisfied with these results, but a loss of as little as 5% of body mass can create large health benefits. Much more difficult than reducing body fat is maintaining its absence. Eighty to ninety-five percent of those who lose 10% or more of their body mass through dieting regain their lost body mass within two to five years.
The body has systems that maintain its homeostasis, including body weight, at certain set points. Therefore, keeping weight off generally requires making exercise and healthy eating a permanent part of a person's lifestyle. Certain nutrients or chemicals, such as phenylalanine, are natural appetite suppressants which allow the body to reset its set point with regard to body weight. However, dieting, exercise, and/or appetite suppressants may not result in sufficient weight loss in patients with serious medical conditions.
An alternative mechanism for hunger suppression might require decreasing the rate of gastric emptying without the ingestion of chemicals in an effort to regulate satiety. It should be understood that the effects of regulating satiety may vary between individuals.
Partially undigested food in the GI tract is generally referred to as chyme. Satiety receptors are generally located all along the stomach. If chyme remains in the stomach for a longer period of time than it naturally would before flowing into the small intestine, the satiety receptors have a greater chance of being activated to signal the sensation of being satiated.
Therefore, a need exists for a device that is structured to inhibit the rate that chyme passes through the GI tract while allowing natural peristaltic action to occur. Such a device would, in effect, regulate satiety and control body mass, and thus obesity, through its implantation in the GI tract. Also, such a device implanted in the stomach and/or small intestine would enhance the ability of an overweight or obese patient to feel satiated so that the patient does not overeat, but rather eat less than normal.
There also exists a need for a novel method of implanting such a device in the pyloric region of the GI tract. Generally, such a device would enter the GI tract endoscopically and would pass through an endoscope in an unexpanded or compressed form. After the device has passed through the endoscope and is implanted in the region, the device preferably would expand to fit securely against tissue surrounding the region such that the position of the device is substantially maintained throughout the digestive process.